Study On Flexible Piezo-Resistive Sensor With Conductive Nanocomposite Polymer Embedded Structure

Sensor is one of the necessary means for measurement,control,digitization,and intelligent automation systems.With the rapid development of health detection,electronic skin,wearable devices,and intelligent robots,the demand for flexible pressure sensors is increasing.More and more researchers have focused on the preparation of high-performance flexible pressure sensors,and the key to successful preparation lies in the selection of pressure sensitive materials and the design of device structures.Aiming at the problems of complex fabrication processes,high cost,and unstable performance,this paper proposes a method of combining template imprinting replication technology with scratch coating nanocomposites to fabricate a flexible piezoresistive sensor with interdigital electrodes and a cylindrical double layer microstructure.The components of the sensor were characterized,and then the performance of the flexible piezoresistive sensor was tested and analyzed.Finally,its application environment was explored.The specific research content is as follows:（1）The Si molds with a circular hole array microstructure and interdigital electrode microchannels were prepared by photolithography and etching technology,and then the microstructure was transferred to the ESSIL296 silicone rubber mold using template imprinting replication technology.The surface morphology was observed using a light microscope,verifying the feasibility of this technology.（2）Graphene–Silver Nanosheet–Polymer Nanocomposite was prepared.Scanning electron microscopy（SEM）was used to characterize the excellent mixing characteristics of the sensor sensitive functional layer polymer nanocomposite,and its good pressure sensitive performance was verified.（3）Using a circular hole array ESSIL296 mold and a interdigital electrode mold,a sensor substrate with a cylindrical array microstructure and astructure of interdigital electrode microchannels was prepared by imprinting technology,and graphene ink was scraped and coated in the interdigital electrode microchannels to prepare a graphene filled embedded interdigital electrode,and then a layer with a thickness of 100μm was scraped and coated above the embedded interdigital electrode.A flexible piezoresistive sensor was prepared by drying graphene–silver nanosheet–polymer nanocomposite pressure-sensitive material and spin coating PDMS colloid.（4）The response characteristics,sensitivity,and stability of the prepared flexible pressure sensor were analyzed through repeated tests,The response performance,sensitivity,and stability of the sensor are investigated.The test results show that the initial resistance of the pressure sensor is only 1.6Ω,the sensitivity is 0.04 k Pa^-1,and the response time is about 286ms.（5）In addition,a highly hydrophobic wetting property can be observed on the functional structure surface of the sensor.The contact angle is 137.2 degrees,revealing the self-cleaning property of the sensor.Verify the dustproof and self-cleaning characteristics of the sensor.Finally,the prepared flexible piezoresistive sensor was applied to the fingers and body sensing robot grippers,demonstrating the testing process of tapping and grasping,and demonstrating its good application prospects.